Some scholars believe that the Elven people were once the advanced intellects and skilled magicians/scientists of Atlantis and that the diaspora (the move of race from one part of the globe to another) occurred when Atlantean floods sent millions off to various parts of the world to establish in new countries, including Ireland. This would signify their presence on Earth anywhere from 10-40,000 years ago, and in Ireland as late as about 5,000 years ago.
Other esoteric philosophers and visionaries have expressed that Elven people came from the Lemurian race, a race of light beings on the lost continent of Lemur. This would put the Elven people more than 50,000 years in the past on this planet. Still others hold to the most recent ideals that are taught in our history books, that the Elven and Fae are imaginary beings and the civilized world began merely a few thousand years ago.
Personally I would like to suggest that, as the legend tells of the Tuatha de Danann, the Elven people, live in an entirely parallel dimension in the present time, that they are calling to us and that many of us are children of the Goddess Danu, the Earth Goddess.
Whatever you believe, it is clear that millions of people feel a connection to the Elven race in some way or another, and that a greater understanding of our connection could bring us unprecedented wisdom along with a boundless love of Nature and the Earth itself.
Though Elven World, the Restoration of the Tuatha De Danann Kingdom is based around these ideas, it is purely a romance and adventure story for your pleasure.